What security concern was noted at Fresno State during the environmental conference?

The noted security concern at Fresno State during the environmental conference was heavy security due to links to eco-terrorism. This indicates that there were fears of potential threats arising from extremist environmental groups known for using aggressive tactics to advocate for their causes.

In this context, the heightened security measures aim to protect participants and ensure the event proceeds without incident. Such concerns stem from historical instances where conferences centered around environmental issues have been targeted by groups that may resort to radical actions to express their discontent or to protest governmental and corporate policies regarding environmental degradation.

The other options suggest various security-related issues, but they do not accurately capture the specific threat level associated with eco-terrorism that necessitated heightened security at the conference. This understanding reinforces the importance of evaluating security measures in light of current events and the potential for extreme reactions from radical factions within activist movements.